Dowel pin



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G. R. RUSK 3,472,312

A TTOE/VEY United States Patent 3,472,312 DOWEL PIN Gerald R.'Rusk',Maumee, Ohio (1152 E. Broadway, Toledo, Ohio 43609) Original applicationApr. 18, 1966, Ser. No. 543,364, now Patent No. 3,354,756, dated Nov.28,1967. Divided and this application Nov. 6, 1967, Ser. No. 703,493

- Int. Cl. 1322c 21/02, 21/08. US. Cl. 164.-387 6. Claims ABSTRACT OFTHE DISCLOSURE A dowel pin for use with a wrench having a tubularportion which slips over and engages the dowel pin, and which dowel pinengaging portion of the wrench-has aligned lateral openings therein. Thedowel pin is hardened so as to be substantially nonmachineable and iscaused to include an opening through the portion that is engaged by thewrench. The dowel pinopening ispositioned so that it is in alignmentwith the openings of the wrench when engaged thereby, for the, purposeof receiving a torque pin when the normal wrench engaging surfaces areno longer adequate.

RELATED APPLICATIONS The present application is a division of copendingapplication Ser. No. 543,364, filed Apr/18, 1966, now PatentNo.3,354,756.

The present invention relates to dowel pins which mate with bushings toalign core boxes, molds, patterns, or other parts in bookedrelationship; andto wrenches for torquing the pins into threadedopeningsof the core boxes, molds, patterns, or other parts. 1

Core boxes are conventionally booked to pattern plates by means ofmating pins and bushing and are thereafter filled with sand or resincontaining compounds that become hard when the boxes are heated. Thecore boxes containing the mold material having half impressions of thepattern therein are lined and booked with these same pins and bushings."The pins and bushings are conventionally provided with threaded shankportions which are screwed into threaded openings in the respective coreboxes. The core boxes with the bushings and pins therein are heated to500 F. or over to harden the mold material and may be stored in colddamp places when not in use. The result is that these pins and'bushingsbecome frozen in the core boxes after a period of time. v

The pins and bushings of coreboxes are subject to. a considerable amountof wearfand'abrasion byireasoriof the sand or moldmaterial which isalwayspresent. After a period of time therefore, it is necessary toreplace the pins and the bushings. All of the pins with which I amfamiliar have either a cylindrical shank for'pressinginto the core boxesor a threaded shank for threading into the core boxes and include aflangeon the outer end thereof with a pin or guide portion projectingoutwardlyof the flange. The pin or guide portion has a cylindricalsection adjacent the flange and a tapered section outwardly of thecylindrical section for guiding a bushing onto the cylindrical centeringsection of the pin. One type of pin which has been used heretofore isshown in US. Kindt Patent 1,455,793" wherein the extreme end section ofthe projecting pin outwardly of the centering portion is provided with asquare shape for the reception of a wrench for screwing the shankportion into a core box. The only way that these pins caribe removedfrom their core boxes in a single piece is by applying torque to awrench positioned on the polygonal section, and in a great manyinstances, the' projecting pin portion is 3,472,312 Patented Oct. .14,1969 twisted oil of the shank portion when the shank portion is frozenin a core box. Once the pin portion istwisted off, it is necessary todrill out or otherwise remove *the shank portion. This procedure is notonlytime consuming and expensive, because the pins are usually quitehard, but in a great many instances, the core boxis damaged. N t v t aAnother type of pin which is commonly used is shown in the Kindt Patent2,451,747. This construction of pin is generally similar to the pinabove described excepting that the surfaces for reception of a wrenchare formed by two notches in the sides of the flange. The flange of thepin fits into a counter bore inthe top surface of the core box. These,pins are torqued into and, out of their threaded receiving openings inthe .core, boxes by a wrench having a pair of axially extending tangs orprojections which fit into the space formed by the sidewalls of thecounter bore and the slotted openings of the flange. After a period oftime, these wrench receiving openings become filled with a hard debriswhich make it impossible for good wrench engagement, and in otherinstances, these wrench receiving openings become Worn and rounded byabrasion, so that the wrench slips out of these openings when anappreciable amount of torque is applied thereto. When this happens, itis necessary to cut off the pin. and drill out the shank portion in asimilar manner to that above described. If the pin has been hardened, itmay be impossible to remove.

An object of the invention is the provision of a new and improved guidepin having an extremely hard surface for increased life and which isprovided with means which will make possible its removal from a core boxwhen its normally used wrench engaging surfaces are damaged or areinsuflicient to effect removal.

Another object of the invention is the provision of a new and improvedguide pin of the above described type having an opening through itsguide portion adjacent the flange. 7

Another object of the invention is the provision of a new and improvedsocket wrench constructed and arranged for use with guide pins of theimmediately above described type and which in addition to conventionalpart gripping surfaces includes lateral openings for alignment with theabove mentioned lateral opening in the guide pm.

Another object of the invention is the provision of a 7 new and improvedguide pin of the above described type surfaces of a size and shape to,receive. an open end wrench and whereby additional torque can be appliedto the pins. 1 A still further object of the invention is the provisionof a new and improved wrench of the above described type which is notsubstantially weakened by the lateral openings therein. x

The invention resides in certain constructions and combinations andarrangements of parts, and further objects and advantages will becomeapparent to those skilled in the art to which the invention relates,from the follow ing description of several preferred embodiments'described with reference to theaccompanying drawing forming a part ofthis specification, and in which:

FIG. 1 is an elevational view of a guide pin for core boxes and thelike,'and which embodies principles of the present invention;

FIG. 2 is a plan view'of the pin shown in FIG. 1; FIG. 3 is anelevational view of a wrench embodying to the guide pin of FIG. 1.;

FIG.4 is an elevational view similar to FIG. 3 but with portions brokenaway to better illustrate the internal detail of the wrench; and

FIG. 5 is a fragmentary sectional view through the dowel pin and dowelbushing of the invention when booked together to align core boxes.

In order that dowel pins will have an extremely long life, his proposedto harden dowel pins to a substantially nonmachinable condition. It isrecognized that should the normally used Wrench engaging surfaces becomenonusable or broken off dowel pins thus hardened could not be drilledout of a core box without damage to the core box.'According to theinvention, second means are provided on the dowel pin to aid in itsremoval when its normally used wrench engaging surfaces are insufficientfor its removal. This second means preferably in 'cludes a lateralopening through the projecting pin portion of the dowel pin adjacent theflange of the dowel pin. The lateral opening is preferably formed beforethe dowel pin is heat treated to its substantially non-machinablecondition. Also according to the invention, a hardened wrench to be usedwith the dowel pin is also provided with openings arranged to align withthe lateral opening through the dowel pin to receive projecting ends ofa pin extending through the opening through the dowel pin.

The guide pin shown in the drawing generally comprises a cylindricallyshaped shank 12 having a flange 14 at one end and external threads 16 onits other end for threaded engagement with a core box 18, a portion ofwhich is shown in FIG. 5. The shank 12 may also include a cylindricalpilot bearing section 20 adjacent to flange 14. The guide pin 10 alsoincludes an axially extending projecting pin portion 22 having acylindrical bushing bearing surface 24, and an outer tapered guidesection 26 for piloting or guiding the bushing on to the bearing section24. The guide pin 10 also includes wrench receiving means whichpreferably includes both a portion 28 on the pin portion 22 and anotherportion 30 on the flange 14. The portion 28 of the wrench receivingmeans comprises a polygonal shaped (usually square) section of the pinon the end of the tapered guide section 26. The portion 30 of the wrenchreceiving means comprises two or more notched out sections of the flange14 to provide flat side surfaces 32 for abutment by a wrench. A lateralopening 34 is provided through the cylindrical bearing section 24preferably located adjacent the flange 14 for reasons which will laterbe apparent.

The guide pin .10 is threaded into and removed from receiving openingsin core boxes and the like by means of the wrench 36 shown in FIGS. 3and 4. The wrench, shown, includes a tubular end portion 38 having anaxially extending opening 40 therein for receiving the pin portion 22 ofthe guide pin 10. The opening 40 includes a cylindrical section 42, thesidewalls of which have a sliding fit with the cylindrical bearingsection 24 ofthe guide pin 10. The sidewalls also include a polygonalshaped section 44 which, in the present instance, is square and whichhave a sliding fit with respect to the polygonal shaped section 28 ofthe wrench receiving means of the guide pin 10. The sidewalls of thepolygonal shaped section 44 will of course transmit torque to theportion 28 of the wrench receiving means. The lower end 46 of the wrench36 is constructed and arranged to bear against the top surface of theflange 14 of the guide pin 10. The wrench 36. is also provided withtangs or projections 48 which project longitudinally from the lowersurface 46, and which are in like number and arrangement with respect tothe notches 30 in the flange 14, so that they can slide into the notches30 and engage the side surfaces 32 when the sidewalls of the polygonalsection 44 engage the wrench receiving means 28 of the guide pin 10. Theradially outer surfaces 50 of the tangs 48 preferably do not extendradially outwardly of the radially outer surface of the flange 14. Thewrench 36 also includes lateral openings 52 of a number and arrangementto align with the opening 34 of the guide pin when the lower surface 46of the wrench 36 engages the upper surface of the flange 14. In theembodiment shown in the drawing, the openings 52 extend through thesidewalls of the wrench 36.

The guide pin 10 is threaded into the core box 18 by engagement of thepolygonal shaped sidewalls of the section 44 of the opening 40 with thepolygonal section 28 of the guide pin 10, or by the engagement of thetangs 48 with the abutment surfaces 32, and preferably both. Duringmanufacture the guide pins 10 are provided with the configuration shown,and are thereafter hardenedby heat treatment to a condition which makesthem substantially non-machinable. If after insertion into a core box.the guide pin 10 should become frozen to a degree wherein suflicientdriving engagement cannot be had between the wrench 36 and the wrenchreceiving means 28 and 30, the wrench 36 can be positioned on the guidepin with its openings 52 aligned with the opening 34 of the guide pin,and a hardened drill rod or the like inserted therethrough. The openings52 need not in all instances extend completely through the sidewalls ofthe wrench 3'6, but may in some instances, be portions of slotscommunicating with the end surface 46 of the wrench for receiving ashort section of pin that extends outwardly of the cylindrical bearingsection 24 of the pin.

The construction so far described, can be used with guide pins havingcylindrical bearing sections 24 that are not joined to the flange 14 bymeans of the fillet 54 shown in the drawing. The openings 34 and 52 maybe spaced outwardly from the top surface of the flange 14 and the end 46of the wrench, respectively. This will allow sufficient metal in thewrench between the openings 52 and the end surface of the wrench totransmit stress around the opening. In the preferred embodiment,however, the openings 52 are positioned above the tangs 48 to furtherincrease the amount of metal in the wrench capable of transmittingstress around the openings 52. Where the openings 52 are positioned overthe tangs 48 and the tangs are provided with suflicient width, theopenings 34 in the guide pins 10 can be positioned very closely adjacentthe top surface of the flange 14 to thereby increase the amount oftorque which can be transmitted from the pin portion 22 to the shankportion 12. In the most preferred construction, a fillet 54 is providedat the juncture between the pin portion 22 and the flange 14, andopening 34 is positioned closely adjacent the flange 14 so as to passthrough part of the fillet 54, and thereby further increase the amountof torque which can be transmitted by a pin in the opening 34 to theshank portion 12.

While the invention has been described with considerable detail, I donot wish to be limited to the particular embodiment shown and described;and it is my intention to cover hereby, all noval adaptations,modifications, and arrangements thereof which come within the practiceof those skilled in the art to which the invention relates, and whichcome within the scope of the following claims.

I claim:

1. For combination with a wrench that comprises a tubular body portionthat has an axially extending opening having surfaces that are shaped toengage a guide pin, and abutment means for torquing threaded guide pinsinto and out of receiving openings in core boxes and the like, saidtubular body portion having lateral openings through its pin engagingsidewalls for receiving a torque pin when inserted transversely throughthe lateral openings; a guide pin comprising: a body member having anaxially extending generally cylindrical shank with a flange portion atone end and external threads adjacent its other end for securing thebody in a threaded opening, said body member also having an axiallyextending guide pin portion projecting from the flanged end of saidshank portion, said guide pin portion having a generally cylindricalsection adjacent said flange and being hardened to a substantiallynonmachineable condition, one of said flange and guide pin portionshaving wrench receiving abutment means for torquing said threaded shankinto a receiving member, and said substantially nonmachineable guide pinportion having a transverse opening therethrough posi tioned to alignwith the openings of the wrench when superimposed on said guide pin.

2. The guide pin of claim 1 wherein said wrench receiving abutment meanscomprises a section of said pin portion outwardly of said cylindricalsection and of a polygonal cross section.

3. The guide pin of claim 1 wherein said wrench receiving abutment meanscomprises notched out sections of said flange portion.

4. The guide pin of claim 2 wherein said flange portion also includeswrench receiving notched out sections.

5. The guide pin of claim 1 having a fillet at the juncture of saidaxially extending guide pin portion and said flanged end of said shank,and wherein said transverse opening extends through said fillet.

References Cited UNITED STATES PATENTS 2,451,747 10/1948 Kindt 164 -2492,533,894 12/1950 Podell 287125 X 3,379,239 4/1968 Rusk et a1. 164-387J. SPENCER OVERHOLSER, Primary Examiner ROBERT D. BALDWIN, AssistantExaminer US. Cl. X.R. 164-412

